1. Technical Field
The present invention generally relates to crankshafts and, more particularly, to a crankshaft structure having a variable-throw crankpin. Specifically, the present invention relates to a crank shaft having a variable-throw crankpin that may be adjusted while the crankshaft is in use.
2. Background Information
Numerous machines known in the art require an eccentrically rotating crankpin that drives a piston or connecting arm back and forth. Such machines typically include pumps where a plurality of pistons may be connected to a single crankpin to move a larger volume of fluid with the pump. One type of pump using a crankshaft is a hydraulic pump. Hydraulic pumps are typically use to drive hydraulic drive mechanisms. Numerous applications require the delivery of the fluid to the mechanism to be varied. Variable stroke pumps may be used in these applications. These applications generally desire that the adjustment of the drive stroke occur while the crankshaft is in use.
In view of the foregoing, an objective of the present invention is to provide a variable stroke crankshaft assembly.
Another objective of the present invention is to provide a variable stroke crankshaft assembly that may be adjusted while the crankshaft is in use.
Another objective of the present invention is to provide a variable stroke crankshaft assembly that allows more than one piston or connecting arm to be connected to the crankpin of the assembly.
Another objective of the present invention is to provide a variable stroke crankshaft assembly that encloses all of the components but for the crankpin so that they may be readily lubricated during operation.
Another objective of the present invention is to provide a variable stroke crankshaft assembly that allows the user to adjust the stroke of the pistons by manipulating a hands lever.
These and other objectives of the invention are achieved by a variable stroke crankshaft assembly including a drive shaft having a rotational axis; the drive shaft having a first end and a second end; the drive shaft defining a longitudinal bore having a centerline; the longitudinal bore having a first end and a second end; the first end of the longitudinal bore positioned at the first end of the drive shaft; the centerline of the longitudinal bore being offset from the rotational axis of the drive shaft; the drive shaft defining a window at the second end of the longitudinal bore; a sleeve disposed around a portion of the drive shaft; the sleeve having an inner surface; the sleeve being slidably mounted on the drive shaft; the sleeve defining at least one angled slot on its inner surface; the slot being disposed over the window; a crankshaft disposed in the longitudinal bore of the drive shaft; the crankshaft including at least one gear tooth projecting out of the window of the drive shaft; the gear tooth of the crank shaft being disposed in the at least one angled slot of the sleeve; the crankshaft having a crankpin; the crankpin having a longitudinal axis; and the crankpin being offset from the longitudinal axis of the main shaft of the crankshaft.
Other objectives and advantages of the invention are achieved by a variable stroke crankshaft assembly that includes a drive shaft having a rotational axis; a sleeve surrounding a portion of the drive shaft; the sleeve being slidably mounted on the drive shaft and connected to the drive shaft so that the sleeve rotates with the drive shaft; a crankshaft carried by the drive shaft; the crankshaft having a main shaft having a longitudinal axis that is offset from the rotational axis of the drive shaft; the crankshaft engaging the sleeve; the crankshaft having a crankpin offset from the longitudinal axis of the drive shaft; and sliding movement of the sleeve rotating the crankshaft to pivot the crankpin and thus change the stroke of the crankshaft assembly.